3. Importance measuresThe second major difficulty facing IPA, and the focus ofthis paper, is the measurement of importance and performance.In this regard, performance has generally been less controversialthan importance: the usual measurement procedure hasbeen to take the mean of the performance ratings obtainedfrom an appropriate group of people by means of a metric orLikert scale. However, a variety of means exist to performimportance measurement. In particular, two quite differentkinds of measure are common in IPA applications: 1) directmeasures based on Likert scale, k-point scale or metric ratingsobtained in the same way as for performance; and 2) indirectmeasures obtained from the performance ratings, either bymultivariate regression of an overall product or service ratingon the ratings given to the individual attributes (Danaher andMattsson, 1994; Dolinsky, 1991; Neslin, 1981; Taylor, 1997;Wittink and Bayer, 1994) or by means of conjoint analysistechniques (Danaher, 1997; DeSarbo et al., 1994; Ostrom andIacobucci, 1995).